Chemoradiotherapy efficacy is predicted by intra-tumour CD8+/FoxP3+ double positive T cell density in locally advanced N2 non-small-cell lung carcinoma.

BACKGROUND: Radiotherapy is a standard of care for locally advanced stage III N2 non-small-cell lung carcinoma (NSCLC) combined with surgery/chemotherapy. Radiotherapy is hypothesised to induce tumour immunogenic cell death, to release neoantigen resulting in intra-tumoural immune infiltration and abscopal effect. Conversely, it has not been demonstrated if immune cells are necessary to drive radiotherapy efficacy and predict patient's survival. PATIENTS AND METHODS: We retrospectively analysed tumour samples and clinical data from 113 patients, 89 resected (PORT) and 24 non-resected (DRC) N2-NSCLC treated with chemotherapy and radiotherapy (same radiotherapy department from 2002 to 2015). The immune environment was characterised with in situ multiplex staining (CD8, FoxP3, PD-L1 and cytokeratin) and correlated with clinical data and survival. RESULTS: High density of CD8+ T cells was associated with OS (p = 0.04, HR = 1.93 [0.99-3.78]) and DFS (p = 0.003, HR = 2.42 [1.31-4.47]) in the PORT. High density of CD8+/FoxP3+ double positive cells was associated with OS (p = 0.01, HR = 1.97 [1.11-3.48]) in the whole population, with OS (p = 0.05, HR = 1.92 [0.98-3.74]) and PFS (p = 0.03, HR = 1.83 [1.03-3.23]) in the PORT without reaching significance for the DRC. Intermediate PD-L1 expression in tumour cells (TPS = 1-49%) was associated with a higher survival in the PORT. CONCLUSIONS: Intra-tumoural CD8+ T cell and particularly CD8+/FoxP3+ double positive T cell densities predict survival in stage III N2-NSCLC suggesting the need for a pre-existing intra-tumour immunity to mediate the action of radiotherapy. Density of CD8+/FoxP3+ cells was the best predictor of patient's survival in multivariate analysis and could represent a biomarker of radiotherapy efficacy.

[Biomarkers predictive of PD1/PD-L1 immunotherapy in non-small cell lung cancer]. / Biomarqueurs prédictifs de l'immunothérapie anti-PD1/PD-L1 dans le cancer broncho-pulmonaire non à petites cellules.

Immune checkpoint inhibitors (ICI), targeting the PD1/PD-L1 axis has shown their efficacy in lung cancer but only in a restricted population of patients, thus it is mandatory to identify biomarkers predicting the clinical benefit. In this article we will describe and analyzed biomarkers already published, from protein, to RNA and at last DNA markers, discussing each markers feasibility and interest. In the future, combined analysis of several markers will probably be proposed, particularly with the increasing complexity of therapy schema with molecules association.

[Analysis of immune microenvironment by multiplex immunohistochemistry in locally advanced non-small cell lung cancer: Principles and perspectives]. / Analyse du microenvironnement immunitaire par immunohistochimie multiplex dans le cancer bronchopulmonaire non à petites cellules localement évolué : principes et perspectives.

Recent therapeutic advances in non-small cell lung cancer allow a better understanding of the interactions between the tumour and its direct immune environment. The identification of new immune biomarkers integrating both cell subpopulations and their interactions is a real issue in oncology. New techniques of tissue analysis, particularly multiplex immunohistochemistry, consisting of a labelling of several antigens of interest by immunofluorescence on the same slide, provide a better understanding of the tumour environment. Integration of these modalities of analysis to the therapeutic decision is promising, because it allows an increased characterization of each tumour, particularly interesting with radiotherapy and immunotherapy. This article describes the potential of these assays in locally advanced non-small cell lung cancer.